BlogDoFT.Libs.EntityFramework.CodeGenerator.Abstractions 1.10.0

BlogDoFT.Libs.EntityFramework.CodeGenerator.Abstractions

Strongly-typed attributes and enums used by the Predicate Generator.

These annotations are applied to filter DTOs so a source generator can emit ToPredicate() and HasFilter() methods.

Target Frameworks: netstandard2.0
C# Language Version: C# 11+ (required for generic attributes)

Contents

• GeneratePredicateAttribute<TEntity>
• StringFilterAttribute
• NumericFilterAttribute
• TemporalFilterAttribute
• BooleanFilterAttribute
• ComparisonOperator enum

Installation

Install it in the app project:

dotnet add package BlogDoFT.Libs.EntityFramework.CodeGenerator.Abstractions

Usage

Annotate your filter DTO with [GeneratePredicate<TEntity>] and mark each filterable property with the respective attribute.

using BlogDoFT.Libs.EntityFramework.CodeGenerator.Abstractions;

[GeneratePredicate<Domain.UserRecord>]
public partial class UserFilterDto
{
    [StringFilter(TargetProperty = nameof(Domain.UserRecord.Name), Order = 1)]
    public string? Name { get; init; }

    [StringFilter(TargetProperty = nameof(Domain.UserRecord.Email), Order = 2)]
    public string? Email { get; init; }

    [NumericFilter(TargetProperty = nameof(Domain.UserRecord.Age),
                   Operator = ComparisonOperator.GreaterThanOrEqual, Order = 3)]
    public int? MinimumAge { get; init; }

    [TemporalFilter(TargetProperty = nameof(Domain.UserRecord.CreatedAt),
                    Operator = ComparisonOperator.LessThanOrEqual, Order = 4)]
    public DateTime? CreatedUntil { get; init; }

    [BooleanFilter(TargetProperty = nameof(Domain.UserRecord.Active), Order = 5)]
    public bool? Active { get; init; }
}

The DTO must be partial. The generator adds the methods into the same type.

Behavior

Generated methods

Generated methods

• Expression<Func<TEntity, bool>> ToPredicate()
• bool HasFilter()

HasFilter() returns true if at least one annotated property holds a non-null value. ToPredicate() returns entity => true when all annotated values are null; otherwise it combines only the provided filters with logical AND.

String wildcards

When the string value contains %, the pattern is passed to the database (LIKE):

• No % → equality (field == value)
• Ends with % → database pattern (e.g., value%)
• Starts with % → database pattern (e.g., %value)
• % in the middle or both sides → database pattern (e.g., %val%ue%)

This relies on the generator’s provider-aware output (see the Generator README).

Numeric and temporal operators

NumericFilterAttribute and TemporalFilterAttribute accept Operator: ComparisonOperator:

• Equal, GreaterThan, LessThan, GreaterThanOrEqual, LessThanOrEqual.

Boolean properties

Always compared by equality.

Query Order

Usually, the where field orders matters - for database index usage.

Filters are composed by Order (if specified). Otherwise, DTO declaration order is used.

Requirements

C# 11+ (for generic attributes)

Works with EF Core 6/7/8+ (generator handles provider-specific differences)